The Link Aggregation Control Protocol (LACP) provides a port negotiation manner for devices that run the protocol to exchange data. After a link aggregation group is established between two devices based on the LACP, higher bandwidth and reliability are provided for communication between the two devices.
In the prior art, establishment and maintenance of a link aggregation group between two devices according to LACP negotiation are implemented through interactions of Link Aggregation Control Protocol Data Units (LACPDUs), that is, LACP packets. Further, after enabled with the LACP, a port of a device sends an LACP packet to a peer device to notify the peer device of information such as a system priority, a system media access control (MAC) address, a port priority, a port number, and an operation key of the device. After receiving the LACP packet, the peer device selects a port that can be aggregated according to the foregoing information in the LACP packet. After performing the foregoing operations, both devices may agree on whether a respective port is selected, thereby determining whether a link can be added to a link aggregation group.
In an actual application, however, to implement interconnections between long distance devices, usually a relay device needs to be employed to forward data, that is, an indirect connection scenario. Therefore, how to implement LACP negotiation between indirectly connected devices is an urgent problem to be solved.